RESUMEN
Kyllinga brevifolia Rottb., Cyperaceae, rhizomes have been widely used in the Paraguayan folk medicine as digestive, diuretic, sedative, tonic, antispasmodic and sudorific. The purpose of this study is to characterize the putative sedative, anxiolytic effects of the crude hydro-ethanolic extract (CEKb) and fractions of the rhizome of K. brevifolia, in male mice. The behaviour of mice was assessed in the open field, hole board, rota-rod and elevated plus-maze (EPM) test. Oral treatment with single doses of 10, 100 and 1000 mg/kg of CEKb and 10 mg/kg of ethyl acetate fraction (KbF-ethyl-ac) increased the duration of the sleeping time induced by pentobarbital. Oral administration of 1, 10 and 100 mg/kg of CEKb and 0.1, 1 and 10 mg/kg of KbF-ethyl-ac also significantly increased the time-spent and arm entries into open arms of the elevated plus maze (EPM) versus control group. These findings indicate that K. brevifolia exerts a weak sedative and an interesting anxiolytic-like effect in mice and suggest its potential usefulness for the treatment of anxiety in humans.